PCIe Link Training LTSSM & Lane Margining Eye Decoder

PCIe Link Training LTSSM & Lane Margining Eye Decoder | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Network
Input types: textarea, select, checkbox
Output type: html
Sample coverage: 4
API ready: Yes

Overview

Decode PCIe Link Training and Status State Machine (LTSSM) logs and lane margining reports into structured diagnostic summaries. This tool parses state sequences, TS1 and TS2 ordered sets, rate identifiers, and equalization phases across Gen1 through Gen6, while grading receiver eye margins from pcilmr CSV outputs against PCIe Base Specification thresholds with generated SVG heatmaps.

When to use

When troubleshooting PCIe link training failures, down-training, or speed fallback loops across Detect, Polling, Configuration, and Recovery states.
When evaluating receiver eye-margin compliance and signal integrity using Linux pcilmr CSV or key-value data.
When inspecting equalization Phase 1 through Phase 3 progression, lane reversal, and polarity inversion during board bring-up.

How it works

1Paste raw LTSSM state sequences, TS1/TS2 ordered set traces, or pcilmr CSV output into the log text area.
2Select the target PCIe generation or leave it on auto-detection to apply the relevant PCIe Base Specification §8.4.2 eye limits.
3Optionally check the SVG heatmap option to generate visual per-lane eye-width and eye-height margin charts.
4Inspect the decoded state timeline, negotiated speed and width badges, equalization diagnostics, and per-lane margin grades.

Use cases

Link Bring-Up Analysis: Inspect high-speed negotiation and Phase 1 to Phase 3 equalization transitions on prototype boards.
Receiver Margin Qualification: Grade pcilmr margining results across all lanes to verify hardware compliance before production release.
Hardware Fault Isolation: Pinpoint whether link degradation stems from physical polarity issues, lane numbering mismatches, or Recovery timeouts.

Examples

1. Decoding Gen5 Link Training and Speed Change

Hardware Validation Engineer

Background

A prototype PCIe Gen5 x4 endpoint intermittently fails to reach 32 GT/s during link initialization.

Problem

Verify whether the link successfully completes Configuration and full Phase 1/2/3 equalization in Recovery.

How to use

Paste the timestamped LTSSM trace containing Polling, Configuration, and Recovery states, then review the decoded timeline.

{
  "pciGen": "auto",
  "showEyeHeatmap": false
}

Outcome

Displays the negotiated x4 width, rate identifier changes from 0x01 to 0x1F, and validates equalization Phase 1, Phase 2, and Phase 3 completion.

2. Grading Gen4 Receiver Eye Margins from pcilmr

Signal Integrity Engineer

Background

A Linux test run on an NVMe backplane generated a pcilmr CSV report containing eye-width and eye-height measurements.

Problem

Identify failing lanes against PCIe Base Spec minimums and visualize margin distribution across all lanes.

How to use

Paste the 22-column pcilmr CSV output, select Gen4, and enable the eye-margin heatmap SVG option.

FAQ

What input formats are supported by the decoder?

The decoder accepts LTSSM state trace lines, TS1/TS2 ordered set strings, Linux pcilmr -o 22-column CSV data, and key-value margin lines.

How is the PCIe generation determined for margining?

It automatically infers the generation from the minimum eye width (EW Min) column or uses the manual Gen4, Gen5, or Gen6 dropdown selection.

What standard is used to grade lane margins?

Margins are graded as Perfect, Pass, or Fail against PCIe Base Specification Rev 5.0 §8.4.2 minimums and PHY Test Specification recommendations.

Can the tool detect lane reversal and polarity inversion?

Yes, it parses link and lane identifiers, PAD flags, and polarity inversion markers present in the TS1/TS2 ordered set records.

Is data processed locally?

Yes, all LTSSM timeline decoding, specification margin grading, and SVG heatmap generation run directly inside the browser.

{
  "pciGen": "4",
  "showEyeHeatmap": true
}

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Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Decoding Gen5 Link Training and Speed Change

2. Grading Gen4 Receiver Eye Margins from pcilmr

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